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Jeez 15mpg again


SrMichi

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I just put in 13.16 gallons of regular shell then divide by 199 miles i got before it reached E and it came out to 15mpg :frown: jeez i don't drive in the city never in traffic its all highway miles. anyone have a clue on whats wrong?

 

BTW sorry if i posted this in the wrong section did not know where to post it.

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Wow that's not very good at all. When was the last time you did a tune-up, such as plugs/wires, air/fuel filter? It's amazing how much MPG's will drop if those are not changed.

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Do your panel vents work and does your cruise control work? If they don't, you have a vacuum leak somewhere and that will cause a loss of mileage and driveability.

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what kind of driving do you do?

 

Highway driving very very little city driving maybe 1 hour a week

 

Do your panel vents work and does your cruise control work? If they don't, you have a vacuum leak somewhere and that will cause a loss of mileage and driveability.

 

cruise works, so do all the vents :cry:

 

O2 sensor or plugged cat?

 

i believe i changed the O2 Sensor. maybe it unplug? now i remember that the clip thing snapped. if it was unplug would check engine light be on? :confused: i did put it a flowmaster cat during the summer

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i believe i changed the O2 Sensor. maybe it unplug? now i remember that the clip thing snapped. if it was unplug would check engine light be on? :confused: i did put it a flowmaster cat during the summer

 

There's 2 O2 sensors, one before the cat and one after... Do you know which one you replaced? And if it is unplugged, it should throw a SES light... I was more thinking along the lines that it just wasn't functioning correctly than being unplugged...

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Where is the temp gauge running when your driving down the highway?

 

A bit below half way mark. i also have a weird problem with the temp gauge in the mornings when is cold enough the overheating light would turn on for a few seconds until it warms up a bit i change the temp sensor under the thremostat but ppl keep telling me there's another one but i can't find it :confused:. ill try to record the light turning on tomorrow morning, is going to be pretty cold tonight.

 

 

 

i believe i changed the O2 Sensor. maybe it unplug? now i remember that the clip thing snapped. if it was unplug would check engine light be on? :confused: i did put it a flowmaster cat during the summer

 

There's 2 O2 sensors, one before the cat and one after... Do you know which one you replaced? And if it is unplugged, it should throw a SES light... I was more thinking along the lines that it just wasn't functioning correctly than being unplugged...

 

there's one after? i only replace the one before. i looked in autozone web site and only found before one. i guess ill change it again this weekend

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Where is the temp gauge running when your driving down the highway?

 

A bit below half way mark. i also have a weird problem with the temp gauge in the mornings when is cold enough the overheating light would turn on for a few seconds until it warms up a bit i change the temp sensor under the thremostat but ppl keep telling me there's another one but i can't find it :confused:. ill try to record the light turning on tomorrow morning, is going to be pretty cold tonight.

 

 

 

i believe i changed the O2 Sensor. maybe it unplug? now i remember that the clip thing snapped. if it was unplug would check engine light be on? :confused: i did put it a flowmaster cat during the summer

 

There's 2 O2 sensors, one before the cat and one after... Do you know which one you replaced? And if it is unplugged, it should throw a SES light... I was more thinking along the lines that it just wasn't functioning correctly than being unplugged...

 

there's one after? i only replace the one before. i looked in autozone web site and only found before one. i guess ill change it again this weekend

NO. only on 1996 and newer cars.

 

and the sensor you can;'t find is for the gauges only, and is located on the drivers side of the rear head right in the corner. LOOK FOR A SINGLE GREEN WIRE!

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Where is the temp gauge running when your driving down the highway?

 

A bit below half way mark. i also have a weird problem with the temp gauge in the mornings when is cold enough the overheating light would turn on for a few seconds until it warms up a bit i change the temp sensor under the thremostat but ppl keep telling me there's another one but i can't find it :confused:. ill try to record the light turning on tomorrow morning, is going to be pretty cold tonight.

 

 

 

i believe i changed the O2 Sensor. maybe it unplug? now i remember that the clip thing snapped. if it was unplug would check engine light be on? :confused: i did put it a flowmaster cat during the summer

 

There's 2 O2 sensors, one before the cat and one after... Do you know which one you replaced? And if it is unplugged, it should throw a SES light... I was more thinking along the lines that it just wasn't functioning correctly than being unplugged...

 

there's one after? i only replace the one before. i looked in autozone web site and only found before one. i guess ill change it again this weekend

 

Hm.. Can somebody verify if the OBD-1 cars have 2 O2 sensors or just one? Your O2 sensor may not be bad if you recently replaced it... I would probably look for a vacuum leak first before you spend the money on another O2 sensor, since looking for a vac. leak is free... Or maybe even a small fuel leak somewhere...

 

 

EDIT- Thanks for clarifying that Ken, I wasn't sure if the earlier cars had 2 or not...

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Where is the temp gauge running when your driving down the highway?

 

A bit below half way mark. i also have a weird problem with the temp gauge in the mornings when is cold enough the overheating light would turn on for a few seconds until it warms up a bit i change the temp sensor under the thremostat but ppl keep telling me there's another one but i can't find it :confused:. ill try to record the light turning on tomorrow morning, is going to be pretty cold tonight.

 

 

 

i believe i changed the O2 Sensor. maybe it unplug? now i remember that the clip thing snapped. if it was unplug would check engine light be on? :confused: i did put it a flowmaster cat during the summer

 

There's 2 O2 sensors, one before the cat and one after... Do you know which one you replaced? And if it is unplugged, it should throw a SES light... I was more thinking along the lines that it just wasn't functioning correctly than being unplugged...

 

there's one after? i only replace the one before. i looked in autozone web site and only found before one. i guess ill change it again this weekend

NO. only on 1996 and newer cars.

 

and the sensor you can;'t find is for the gauges only, and is located on the drivers side of the rear head right in the corner. LOOK FOR A SINGLE GREEN WIRE!

 

k will check tomorrow during lunch. if it's bad where could i buy a new one?

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Where is the temp gauge running when your driving down the highway?

 

A bit below half way mark. i also have a weird problem with the temp gauge in the mornings when is cold enough the overheating light would turn on for a few seconds until it warms up a bit i change the temp sensor under the thremostat but ppl keep telling me there's another one but i can't find it :confused:. ill try to record the light turning on tomorrow morning, is going to be pretty cold tonight.

 

 

 

i believe i changed the O2 Sensor. maybe it unplug? now i remember that the clip thing snapped. if it was unplug would check engine light be on? :confused: i did put it a flowmaster cat during the summer

 

There's 2 O2 sensors, one before the cat and one after... Do you know which one you replaced? And if it is unplugged, it should throw a SES light... I was more thinking along the lines that it just wasn't functioning correctly than being unplugged...

 

there's one after? i only replace the one before. i looked in autozone web site and only found before one. i guess ill change it again this weekend

 

Hm.. Can somebody verify if the OBD-1 cars have 2 O2 sensors or just one? Your O2 sensor may not be bad if you recently replaced it... I would probably look for a vacuum leak first before you spend the money on another O2 sensor, since looking for a vac. leak is free... Or maybe even a small fuel leak somewhere...

 

 

EDIT- Thanks for clarifying that Ken, I wasn't sure if the earlier cars had 2 or not...

OBDI cars only have one O2 sensor.

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what kind of driving do you do?

 

Highway driving very very little city driving maybe 1 hour a week

 

 

Ok... two more questions: What's your "average" speed? And how long are the highway trips typically? I only ask because my old '90 Cutlass wouldn't do much better than 20 mpg driving 70+ MPH and doing 35 mile trips at almost all Long Island style highways.

 

Few other things to check:

 

- Dragging rear brakes (somewhat common on your car)

- tires under-inflated

- Fuel-related problem (does it start easy, or hard when the engine's cold?)

 

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what kind of driving do you do?

 

Highway driving very very little city driving maybe 1 hour a week

 

 

Ok... two more questions: What's your "average" speed? And how long are the highway trips typically? I only ask because my old '90 Cutlass wouldn't do much better than 20 mpg driving 70+ MPH and doing 35 mile trips at almost all Long Island style highways.

 

Few other things to check:

 

- Dragging rear brakes (somewhat common on your car)

- tires under-inflated

- Fuel-related problem (does it start easy, or hard when the engine's cold?)

 

 

Um lets see work is about 16miles away avg speed is around 65ish

 

- :willynilly: maybe your right when i put new pads i had trouble pushing the piston back in. ill check and if need be change the two rear calipers.

- i put in new tires in dec and check the tire pressure in its at 32psi

- car starts pretty easy

 

how would i go about keeping the rear calipers from dragging?

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well the piston in the rear calipers need to be rotated in order to retract properly. Lots of times, the sliders sieze up (the bushings that the bolts go thru act as sliders) or the parking brake siezes, causing the piston to stick.

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Do you still have torque convert lock up? Are you standing on your accelerator pedal when you accelerate? Pull out some plugs and see what they look like. Does your exhaust smell bad? When is the last time you changed the air filter, ran some injector cleaner? What is the average outside air temperature where you live?

 

Do what every one else is saying and lift the rear of the car, see if the wheels are dragging. I hope you twisted the rear pistons in and didnt use the C-clamp method on them. When the rear wheels are in the air, the wheel should spin with a very slight drag from the brakes. Are your E-brake cables seized? I would imagine if your rear brakes were dragging severly, you would have smelled the pads burning up by now.

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Do you still have torque convert lock up? Are you standing on your accelerator pedal when you accelerate? Pull out some plugs and see what they look like. Does your exhaust smell bad? When is the last time you changed the air filter, ran some injector cleaner? What is the average outside air temperature where you live?

 

Do what every one else is saying and lift the rear of the car, see if the wheels are dragging. I hope you twisted the rear pistons in and didnt use the C-clamp method on them. When the rear wheels are in the air, the wheel should spin with a very slight drag from the brakes. Are your E-brake cables seized? I would imagine if your rear brakes were dragging severly, you would have smelled the pads burning up by now.

 

 

1. Um Did i have a torque convert lock up?

2. No acceleration is good

3. Will do this weekend

4. exhaust Smells good

5. Air Filter changed last summer With K&N filter

6. injector cleaner i think i used one last month

7. Temp outside right now is mid 20s last week was fifties. live in new jersey still winter

 

I did twist the piston back in it took me a while i had to fight with it cause i kept twisting and it would not go in but finally did. will lift car this weekend to spin my rear tires. I always use my E- Brake so i doubt it.

 

one thing i do notice is when going on highway once i let go of pedal i do slow down some what faster than usually.

 

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one thing i do notice is when going on highway once i let go of pedal i do slow down some what faster than usually.

 

 

That could certainly be the rear brakes. Using it frequently doesn't mean it won't freeze up (been there before)

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How long are you letting your car warm up? This also greatly affects your milage. I used to get 15 throughout the winter in my Z24 driving 20 miles each way to work, most of that was contributed to letting it warm up for 10-15 minutes on the colder days. It gets 23-27 drivng it pretty hard normally in the summer. It does also sound like your brakes could be dragging.

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don't forget that the winter blended fuel will make a huge difference on MPG. For example, my Regal normally gets around 37-38 MPG on the highway. I just took a trip a few weeks ago and only manage about 31 MPG. Even just with regular driving, i was constantly getting 28.5 MPG driving to and from work and as soon as they fazed in the winter blend, i immediately dropped down to 26, and this was before the temp even turned cold.

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For example, my Regal normally gets around 37-38 MPG on the highway.

 

37-38 on the highway? can i borrow that regal for a week or two(for confirmation, of course)?

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